(a) Field
The invention relates to a method of manufacturing an organic light emitting diode (“OLED”) display.
(b) Description of the Related Art
Flat panel displays are generally classified into a light emitting type display and a light receiving type display. The light emitting type display includes a flat cathode ray tube, a plasma display panel (“PDP”), an electroluminescent device and a light emitting diode, for example. The light receiving type display includes a liquid crystal display (“LCD”), for example.
Among flat panel displays, the electroluminescent device attracts attention as a next-generation display device due to a wide view angle, high contrast and high response speed.
The electroluminescent device is generally categorized into an inorganic electroluminescent device and an organic electroluminescent device according to a material of an emission layer.
The organic electroluminescent device is a self-luminance display that emits light according to electrical excitation of an organic fluorescent compound and is considered as a next-generation display capable of effectively solving problems of LCDs since the organic electroluminescent device is driven at a substantially low voltage and easily formed in a compact structure, and has a wide view angle and rapid response speed.
The organic electroluminescent device generally includes an emission layer formed of an organic material and interposed between an anode including Indium Tin Oxide (“ITO”), for example, and a cathode.
When positive and negative voltages are respectively applied to the anode and cathode of the organic electroluminescent device, holes injected from the anode are moved to the emission layer via a hole transport layer, electrons injected are moved from the cathode to the emission layer via an electron transport layer and the electrons and holes are recombined in the emission layer, generating excitons.
As the excitons are dropped from an exited state to a ground state, fluorescent molecules of the emission layer emit light, forming an image. A full color organic electroluminescent device includes pixels emitting red (“R”), green (“G”) and blue (“B”) lights to display full-color images.
In the above-described organic electroluminescent device, a pixel definition layer is formed on both ends of the anode.
A predetermined opening is defined in the pixel definition layer and then an organic emission member and the cathode are sequentially formed on the anode exposed through the opening.
The organic emission member may include an organic emission layer and the electron transport layer, an electron injection layer, a hole transport layer and a hole injection layer disposed on top and bottom surfaces of the organic emission layer.